Hello, Finance World!

Hello, Finance World! 👋

This is it - your very first program. Every quant at Goldman Sachs, every economist at the ECB, every data scientist at BlackRock once sat exactly where you are sitting now, about to make a computer say something for the very first time. Today the machine speaks because you tell it to. Welcome aboard 🎉

The print() function

print() displays text on the screen. It's your main tool for showing results.

print("Hello, World!")   # prints:  Hello, World!
print(42)                # prints:  42
print(3.14)              # prints:  3.14

The quotes matter: "Hello, World!" is text (Python calls it a string), and Python displays it exactly as written, character for character. Numbers need no quotes.

🧠 The mental model: the receipt printer

Picture your program as the cash register in a busy café. Inside, it can add, multiply and juggle numbers all day - but all of that happens silently, invisibly, in the machine's memory. print() is the receipt printer: it is the only way the register shows the outside world what it computed. No print(), no receipt - the maths happened, but nobody saw it.

That is why print() is the first thing every programmer learns: it makes the invisible visible.

Basic arithmetic

Python can do maths just like a calculator:

Printing words and numbers together

Give print() several things separated by commas and it shows them on one line, with spaces in between:

total = 1745.5
print("Total cost:", total)   # prints:  Total cost: 1745.5

Your Task

1. Write your first line of code: print the message "Welcome to EcoFinLearn!". The starter has a print("...") waiting for you - replace the three dots with the message (keep the quotes!).
2. Step 2 is already written for you: an AAPL share costs $174.55, you buy 10 shares, and the program prints the total cost.

Predict before you run: what number will the second line show? Multiplying by 10 just slides the decimal point one place to the right - do it in your head with 174.55, then press Run and check. When both lines match, you have officially written your first program. 🥳